The invention (Publication No.: CN200810091185.6) discloses a flushing mechanism for dirt and/or sewage flushing, which comprises a housing with an open upper part and a bottom part having an open mouth at the center. The inner side of the housing defines a plurality of cavities for storing water and accommodating parts. The lower part of the housing is arranged with a plurality of pipes that generate water passes respectively with the cavities defined by the housing; an upper cover, the lower part of which is connected with the housing; a guide rod, with a central line being penetrated through the cavities coinciding with the central line of the housing; a first piston comprising a bottom part with a central hole and a cylindrical part that outstretches to the periphery of the central hole from the bottom part of the first piston. The side of the bottom part of the first piston is arranged with a groove along the radical direction and the cylindrical part of the first piston is in a hollow shape, and the guide rod penetrates the cylindrical part of the first piston and the central hole of the bottom part of the first piston; a seal assembly of the first piston that locates in the groove at the side of the bottom part of the first piston, causing an up-and-down and reciprocating motion of the first piston along the inner wall of the housing in a hermetic manner; a spring loading the first piston, the end of which is fixed at the inner side of the upper cover top of the housing, and the other end of which is fixed on the upper surface of the bottom part of the first piston to apply force on the first piston; a second piston, comprising a bottom part with a central hole and a cylindrical part that outstretches to the periphery of the central hole from the bottom part of the second piston The cylindrical part of the second piston is in a hollow shape, and the guide rod penetrates the cylindrical part of the second piston and the central hole of the bottom part of the second piston; a spring loading the second piston arranged at the surrounding of the guide rod at the inner side of the hollow part of the cylindrical part of the second piston. One end of the spring loading the second piston is fixed at the inner side of the upper part of the cylindrical part of the second piston, and the other end is fixed on the fixed end of the guide rod, wherein, the spring loading the second piston further comprises a pressure-relief and/or bulletproof part that locates in the housing; and the outer periphery of the bottom part of the second piston and the periphery of the central hole are arranged with a seal assembly of the second piston; the seal assemblies of the first piston and the second piston consist of an inner sealing element and an outer sealing element, wherein, the inner sealing element has a spring element bended from a sheet metal and the outer sealing element has an O-ring. The bottom part of the second piston, the seal assembly of the second piston and the bottom part of the housing define an exterior lower cavity and an interior lower cavity, for cooperating with the spring loading the second piston in the course of the drainage, sequentially the second piston is moved upward and the outfall is opened.
The flushing mechanism has the disadvantages that the seal is not stable when the drainage completes and the product life is short.